This invention relates to an attachment for a vacuum pump. In particular, the invention concerns an attachment for evacuating fluid from a container and for introducing new fluid into the container.
The invention has been developed primarily for changing coolant in a cooling system of a vehicle and will therefore be described in this context. It is to be appreciated, however, that the invention may have other uses.
In order to keep a vehicle in good running order, it is important to empty the vehicle""s cooling system of spent coolant and to refill the cooling system with fresh coolant.
The usual method of changing coolant entails opening various ports of the cooling system, such as a radiator cap and a stopcock, and then allowing the coolant to drain from the cooling system under gravity. After the coolant has drained, the stopcock is closed and fresh coolant is poured into the system by way of a neck of the radiator. The neck is then sealed with the radiator cap.
A disadvantage with the aforementioned method is that pockets of air may become trapped in the cooling system. This may happen even if precautions, such as running the engine for a period of time without the radiator cap in place, are taken. It is essential that all pockets of air be removed, else the vehicle""s engine may overheat and suffer damage. Another disadvantage with the method is that a leak in the cooling system may go undetected.
It is an object of the present invention to provide an attachment for a vacuum pump that minimises at least one of the disadvantages referred to above, or provides the public with a useful or commercial choice.
According to the present invention there is provided an attachment for a vacuum pump, for evacuating a first fluid from a container and for introducing a second fluid into the container, said attachment having:
a body having:
a first inlet for the first fluid;
a second inlet for the second fluid;
an outlet;
a passage connecting the outlet to each of the inlets, the outlet being attachable to the vacuum pump and the first inlet being attachable to the container; and
a valve within the passage adjacent the outlet, said valve being moveable between a first position in which the passage is closed and a second position in which the passage is open, the valve being biased to remain in the first position, and whilst a vacuum is applied to the attachment by the vacuum pump, the valve is in the second position and the first fluid may be drawn into the vacuum pump; and
an operating member for regulating the flow of fluid through the second inlet.
Preferably, the attachment is attachable to the vacuum gun described in the specification of PCT/AU01/00127, the entire content of which is incorporated herein by reference. The outlet of the body may be located at the end of a nozzle, and the nozzle may be frictionally attachable to a front end of the vacuum gun. Preferably, the nozzle is further attachable with a locking member such as a lock nut.
The vacuum gun may have a deflector attached to a rear end of the gun for directing the first fluid away from the face of the person using the gun. Preferably, the deflector is a perforated plate, wherein the perforations are orientated to direct the first fluid away from the person""s face.
Preferably, the valve is a jumper valve, the passage has a valve seat, and the jumper valve is biased into the first position against the valve seat. The jumper valve can be biased into the first position with a coil spring.
Preferably, the container is a cooling system of a vehicle and the first inlet is attachable to a neck of a radiator of the cooling system. The coolant within the cooling system may first be drained by opening a stopcock of the radiator. The first fluid is the air occupying the cooling system after the coolant has been drained. The second fluid is fresh coolant that is to be added to the cooling system whilst under vacuum.
The first inlet is preferably located at an end of a resilient (eg. rubber) cone that fits into the neck of the radiator. Preferably, the cone has a stepped periphery that enables attachment to radiator necks of varying diameter.
The operating member that regulates the flow of fluid through the second inlet may be a valve or a tap. Preferably, the operating member is a tap that is attached to the second inlet and a hose extends from the tap to a source of the second fluid.
Preferably, the attachment further has a pressure gauge attached to the body for monitoring the pressure within the passage. Any suitable type of pressure gauge known to persons skilled in the art may be used.
According to a preferred form of the invention, there is provided an attachment for a vacuum pump for introducing new coolant into a cooling system of a vehicle, said attachment having:
a body having:
a resilient cone having an inlet for air from the cooling system of the vehicle after spent coolant has been drained from the cooling system;
an inlet for the new coolant;
a nozzle having an outlet;
a passage connecting the outlet to each of the inlets, the nozzle being attachable to the vacuum pump and the cone being attachable to a neck of a radiator of the cooling system; and
a jumper valve located within the passage adjacent the outlet, said jumper valve being moveable between a first position in which the passage is closed and a second position in which the passage is open, the jumper valve being biased into the first position and movable into the second position when a vacuum is applied to the attachment by the vacuum pump, and when the jumper valve is in the second position, air may be drawn from the cooling system to form a partial vacuum therein;
a tap attached to the inlet for the new coolant and new coolant may be introduced into the cooling system when the system is under vacuum and when the tap is opened;
a hose extending from the tap to a source of the new coolant; and
a pressure gauge attached to the body for monitoring the pressure within the passage.